Keep us posted on how the switch goes. I've been looking at smartphones and the Windows Phone looks to be a contender. One problem I can see for myself is that I have to use a mac at work. If I travel I only take my work computer so I'm not sure if it will play nice with an Apple computer.

I don't know. I have a slider that's probably 5 years old. The only thing wrong (other than some scratches) is that the battery doesn't last as long as it used to. I have to charge it every other day now, I used to be able to go nearly a week without charging it.

While I've never actually installed or developed shopping cart software I'd suggest you don't build it from scratch unless you have a full-time web developer on call. Basically the stuff you buy will have the benefit of many other users finding bugs and will be less likely to have security vulnerabilities.